Add dkim/mkcert to generate DKIM certificates

1 files changed, 51 insertions, 0 deletions

diff --git a/dkim/mkcert b/dkim/mkcert
new file mode 100755
index 0000000..971496f
--- /dev/null
+++ b/dkim/mkcert
@@ -0,0 +1,51 @@
+#!/bin/rc
+
+# This script generates and stores DKIM keypair, using the correct user
+
+dir      = /etc/mail/dkim
+user     =_dkimsign_
+selector = $1
+privkey  = $dir/$selector.priv.key
+pubkey   = $dir/$selector.pub.key
+txt      = $dir/$selector.txt
+
+if (!~ $#* 1) {
+	echo 'usage: mkcert <selector>'
+	exit 2
+}
+
+fn die {
+	echo fatal error: $* >[1=2]
+	exit 1
+}
+
+fn mustsucceed {
+	if (!$*) {
+		echo fatal error: essential command failed >[1=2]
+		cleanupfailed
+		exit 1
+	}
+}
+
+fn cleanupfailed {
+	as rm $privkey
+	as rm $pubkey
+	as rm $txt
+}
+
+fn as {
+	doas -u _dkimsign $*
+}
+
+as test -e $privkey && die $privkey already exists
+as test -e $pubkey  && die $pubkey already exists
+as test -e $txt     && die $txt already exists
+
+mustsucceed as mkdir -p $dir
+
+mustsucceed as openssl genrsa -out $privkey
+mustsucceed as openssl rsa -in $privkey -pubout | \
+	mustsucceed as tee $pubkey >/dev/null
+mustsucceed as cat $pubkey | \
+	mustsucceed as sed '1s/.*/v=DKIM1;p=/;:nl;${s/-----.*//;q;};N;s/\n//g;b nl;' | \
+	mustsucceed as tee $txt >/dev/null